1 files changed, 121 insertions, 0 deletions
diff --git a/arch/microblaze/lib/muldi3.S b/arch/microblaze/lib/muldi3.S
new file mode 100644
index 0000000..ceeaa8c
--- /dev/null
+++ b/arch/microblaze/lib/muldi3.S
@@ -0,0 +1,121 @@
+#include <linux/linkage.h>
+
+/*
+ * Multiply operation for 64 bit integers, for devices with hard multiply
+ *	Input :	Operand1[H] in Reg r5
+ *		Operand1[L] in Reg r6
+ *		Operand2[H] in Reg r7
+ *		Operand2[L] in Reg r8
+ *	Output: Result[H] in Reg r3
+ *		Result[L] in Reg r4
+ *
+ * Explaination:
+ *
+ *	Both the input numbers are divided into 16 bit number as follows
+ *		op1 = A B C D
+ *		op2 = E F G H
+ *	result = D * H
+ *		 + (C * H + D * G) << 16
+ *		 + (B * H + C * G + D * F) << 32
+ *		 + (A * H + B * G + C * F + D * E) << 48
+ *
+ *	Only 64 bits of the output are considered
+ */
+
+	.text
+	.globl	__muldi3
+	.type __muldi3, @function
+	.ent __muldi3
+
+__muldi3:
+	addi	r1, r1, -40
+
+/* Save the input operands on the caller's stack */
+	swi	r5, r1, 44
+	swi	r6, r1, 48
+	swi	r7, r1, 52
+	swi	r8, r1, 56
+
+/* Store all the callee saved registers */
+	sw	r20, r1, r0
+	swi	r21, r1, 4
+	swi	r22, r1, 8
+	swi	r23, r1, 12
+	swi	r24, r1, 16
+	swi	r25, r1, 20
+	swi	r26, r1, 24
+	swi	r27, r1, 28
+
+/* Load all the 16 bit values for A thru H */
+	lhui	r20, r1, 44 /* A */
+	lhui	r21, r1, 46 /* B */
+	lhui	r22, r1, 48 /* C */
+	lhui	r23, r1, 50 /* D */
+	lhui	r24, r1, 52 /* E */
+	lhui	r25, r1, 54 /* F */
+	lhui	r26, r1, 56 /* G */
+	lhui	r27, r1, 58 /* H */
+
+/* D * H ==> LSB of the result on stack ==> Store1 */
+	mul	r9, r23, r27
+	swi	r9, r1, 36 /* Pos2 and Pos3 */
+
+/* Hi (Store1) + C * H + D * G ==> Store2 ==> Pos1 and Pos2 */
+/* Store the carry generated in position 2 for Pos 3 */
+	lhui	r11, r1, 36 /* Pos2 */
+	mul	r9, r22, r27 /* C * H */
+	mul	r10, r23, r26 /* D * G */
+	add	r9, r9, r10
+	addc	r12, r0, r0
+	add	r9, r9, r11
+	addc	r12, r12, r0 /* Store the Carry */
+	shi	r9, r1, 36 /* Store Pos2 */
+	swi	r9, r1, 32
+	lhui	r11, r1, 32
+	shi	r11, r1, 34 /* Store Pos1 */
+
+/* Hi (Store2) + B * H + C * G + D * F ==> Store3 ==> Pos0 and Pos1 */
+	mul	r9, r21, r27 /* B * H */
+	mul	r10, r22, r26 /* C * G */
+	mul	r7, r23, r25 /* D * F */
+	add	r9, r9, r11
+	add	r9, r9, r10
+	add	r9, r9, r7
+	swi	r9, r1, 32 /* Pos0 and Pos1 */
+
+/* Hi (Store3) + A * H + B * G + C * F + D * E ==> Store3 ==> Pos0 */
+	lhui	r11, r1, 32 /* Pos0 */
+	mul	r9, r20, r27 /* A * H */
+	mul	r10, r21, r26 /* B * G */
+	mul	r7, r22, r25 /* C * F */
+	mul	r8, r23, r24 /* D * E */
+	add	r9, r9, r11
+	add 	r9, r9, r10
+	add	r9, r9, r7
+	add	r9, r9, r8
+	sext16	r9, r9 /* Sign extend the MSB */
+	shi	r9, r1, 32
+
+/* Move results to r3 and r4 */
+	lhui	r3, r1, 32
+	add	r3, r3, r12
+	shi	r3, r1, 32
+	lwi	r3, r1, 32 /* Hi Part */
+	lwi	r4, r1, 36 /* Lo Part */
+
+/* Restore Callee saved registers */
+	lw	r20, r1, r0
+	lwi	r21, r1, 4
+	lwi	r22, r1, 8
+	lwi	r23, r1, 12
+	lwi	r24, r1, 16
+	lwi	r25, r1, 20
+	lwi	r26, r1, 24
+	lwi	r27, r1, 28
+
+/* Restore Frame and return */
+	rtsd	r15, 8
+	addi	r1, r1, 40
+
+.size __muldi3, . - __muldi3
+.end __muldi3